udev rule for Wacom pad not working

I have the following script to define the button mappings of my Wacom Intuos S 2: /usr/local/bin/wacom_intuos_s_2_pad_button_mapping.sh

#!/bin/bash

export DISPLAY=:0
export XAUTHORITY=/home/scriptim/.Xauthority
/usr/bin/sleep 1 # wait for device to be ready
/usr/bin/xsetwacom set 'Wacom Intuos S 2 Pad pad' Button 1 'key -'
/usr/bin/xsetwacom set 'Wacom Intuos S 2 Pad pad' Button 3 'key +'
/usr/bin/xsetwacom set 'Wacom Intuos S 2 Pad pad' Button 8 'key +Ctrl z -Ctrl'
/usr/bin/xsetwacom set 'Wacom Intuos S 2 Pad pad' Button 9 'key +Ctrl +Shift z -Ctrl -Shift'

This script works fine if I run it manually. My goal is to run this script automatically whenever the pad is plugged in. I tried that with the following udev rule: /etc/udev/rules.d/10-wacom_intuos_s_2_pad.rules

ACTION=="add", SUBSYSTEMS=="usb", ATTRS{idVendor}=="056a", ATTRS{idProduct}=="033b", RUN+="/usr/local/bin/wacom_intuos_s_2_pad_button_mapping.sh"

**However, the script does not map the buttons if I plug in the pad.** --- Im running Arch Linux (5.5.10-arch1-1)

$ lsusb
...
Bus 004 Device 015: ID 056a:033b Wacom Co., Ltd CTL-490 [Intuos Draw (S)]
...

$ udevadm info -a -n hidraw0
...
  looking at parent device '/devices/pci0000:00/0000:00:10.0/usb4/4-2':
    KERNELS=="4-2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{authorized}=="1"
    ATTRS{bcdDevice}=="0100"
    ATTRS{bmAttributes}=="80"
    ATTRS{bMaxPower}=="498mA"
    ATTRS{manufacturer}=="Wacom Co.,Ltd."
    ATTRS{quirks}=="0x0"
    ATTRS{maxchild}=="0"
    ATTRS{bNumInterfaces}==" 3"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{devpath}=="2"
    ATTRS{ltm_capable}=="no"
    ATTRS{busnum}=="4"
    ATTRS{devnum}=="15"
    ATTRS{tx_lanes}=="1"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{speed}=="12"
    ATTRS{version}==" 2.00"
    ATTRS{product}=="Intuos PS"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{idVendor}=="056a"
    ATTRS{configuration}==""
    ATTRS{devspec}=="(null)"
    ATTRS{urbnum}=="174"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{removable}=="unknown"
    ATTRS{rx_lanes}=="1"
    ATTRS{idProduct}=="033b"
...

$ udevadm test --action="add" /devices/pci0000:00/0000:00:10.0/usb4/4-2
This program is for debugging only, it does not run any program
specified by a RUN key. It may show incorrect results, because
some values may be different, or not available at a simulation run.

Load module index
Parsed configuration file /usr/lib/systemd/network/99-default.link
Created link configuration context.
Reading rules file: /usr/lib/udev/rules.d/10-dm.rules
Reading rules file: /etc/udev/rules.d/10-wacom_intuos_s_2_pad.rules
...
Reading rules file: /usr/lib/udev/rules.d/65-libwacom.rules
...
Reading rules file: /usr/lib/udev/rules.d/wacom.rules
Invalid inotify descriptor.
DEVPATH=/devices/pci0000:00/0000:00:10.0/usb4/4-2
DEVNAME=/dev/bus/usb/004/015
DEVTYPE=usb_device
DRIVER=usb
PRODUCT=56a/33b/100
TYPE=0/0/0
BUSNUM=004
DEVNUM=015
MAJOR=189
MINOR=398
ACTION=add
SUBSYSTEM=usb
ID_VENDOR=Wacom_Co._Ltd.
ID_VENDOR_ENC=Wacom\x20Co.\x2cLtd.
ID_VENDOR_ID=056a
ID_MODEL=Intuos_PS
ID_MODEL_ENC=Intuos\x20PS
ID_MODEL_ID=033b
ID_REVISION=0100
ID_SERIAL=Wacom_Co._Ltd._Intuos_PS
ID_BUS=usb
ID_USB_INTERFACES=:030000:030102:
ID_VENDOR_FROM_DATABASE=Wacom Co., Ltd
ID_MODEL_FROM_DATABASE=CTL-490 [Intuos Draw (S)]
ID_PATH=pci-0000:00:10.0-usb-0:2
ID_PATH_TAG=pci-0000_00_10_0-usb-0_2
USEC_INITIALIZED=4102997566
run: '/usr/local/bin/wacom_intuos_s_2_pad_button_mapping.sh'
Unload module index
Unloaded link configuration context.

$ journalctl -xe
Mar 22 17:38:55 scriptim systemd-udevd: 1-1: Process '/usr/local/bin/wacom_intuos_s_2_pad_button_mapping.sh' failed with exit code 255.