Colors should pretty much match your harness already.
Yellow to yellow (alt. phases)
Black to black (bike power)
White to white (field coil)
Red to red (to battery +)
Green to green (ground/frame/battery -)
Just make sure the green from generator goes to ground, it's easy to just connect that to the regulator, and then it's no good. You can do it that way, but make sure the wire ALSO goes to ground or you'll fry the rectifier. In short: generator green to ground, reg/rect green to ground.