Does your car have a MAP light? If so, do you think you'll ever use it? I'd hook the pump up to the map light switch. If you don't have the map light, I would try to find a map light bezel and install the switch in the same location. There should already be a hole in the dash for it. That would be my first choice.
It looks like you might already have your gauge pod mounted where the map light switch was originally mounted though. Is this electric pump going to run all the time or just used to prime the engine after the car sits? Post a picture of your switch. Since you have a custom interior, I think a switch might look good on the console...directly in front of the shifter. You'd only have to drill a hole into the top plate. Obviously, it depends on what the switch looks like.
