Hullo Stephen, wylcome to Ninjette!!
You have early 1st-gen 500 with single pickup coil. You can find wiring diagram for it by doing Google for "classic early gpz500 wiring diagram". There's hit on classic site with DIR_1667004 which contains PDF.
Then go to this thread where people posted their own minimal diagrams.
https://www.ninjette.org/forums/showthread.php?t=326020