You can edit the colors and pattern of the Notification-LED in:
/etc/mce/20hybris-led.ini
create a backup of this File before editing and be sure to have the developer-mode enabled, in case you have to revert to the original if something bad happen.
then
systemctl restart mce.service
I once had the Idea to create a Options-Entry for editing the LED-Color and Pattern as a Patch. But i don´t feel skilled enough with Patches for this Task. Someone with good SailfishOS-Coding-Knownledge should do it. If someone is interested, i can build and support a static Qt-Page with a possible Design for it.