Tape together thin paper (so you can see the shape below). Trace it out, put that in a safe place. Do the deed, then tape the paper back on. Do some creative razor work so you can "mark" the cabinet side at important places and pull the paper away. Then paint.
If it's a vinyl sideart, bring it in to a paint store. They'll mix something very close.
If you do it right, you could seperate the traced pages and xerox them onto thicker stock. Then tape the thick paper together and you have a stencil.