I haven't found the schematic you are looking for but I have come across a couple resources which may help, depending on whether the wires have come out on the ADB or the USB side of things.

Eserviceinfo.com describes the standard wiring colors for usb cables as:

Pin Name Direction Color Description 1 VCC
Red +5 VDC 2 D-
White target="_blank">Pinout.ru describes the wiring for the ADB bus as:

Pin Name Description 1 ADB Apple Desktop Bus 2 PSW Power Switch 3 +5V Power +5V 4 GND Ground
3 & 4 will be red and black, but the other two aren't mentioned.

Griffin put the iMate out in 1998, so I'm surprised the full schematic is difficult to find.

Good luck, I hope that helps.

I see that your question has gone unanswered since yesterday.
Although I am not sure if there is a way to get a wiring schematic for this device short of buying one and taking it apart.
I will try and help. But first I would like you to give me a list of the colors of the wires.
The reason why is because most devices like this use a specific layout for the wires. In other words a USB mouse will have the same combination as the internal plug that connects the front accessory USB plug to the motherboard. I know this because I have a bad habit of taking these things apart. Fortunately I am pretty good at putting them back together. Granted they don't always work the same way but that's mostly confined to annoying family and friends things I fix. :-}
Anyway while I wait I'll try and hunt down a schematic just in case there is one out there to be found.