Not sure of a custom overlay of an ARTCC sector map. Look here FAA Sectionals as Skyview Map for how to access terminal area charts, sectionals and IFR area/high altitude maps built in to dump1090. Unfortunately these aren’t exactly what you’d need.
For someone so inclined I suppose you could take the ARTCC sector map and overlay it with transparency on the standard map and integrate this to your dump1090 (a bit out of my depth on how this might work).