love live

How should I go about making an IO harness? I gotta connect 43 pins to 43 other pins on the button board and I only need 2-3 feet (~ 100 cm) in length. This is for a TTX4 Love Live machine I'm building (I'll post pictures when its all done) I could cut a bunch of ethernet wire and spend hours...

Does anyone have scans of either one of these manuals? I'm interested in what they have inside ...