This is a really good question as I only know from trial and error - not sure if there is a guide out there.
So you want to keep the things like LFO's and other modulation sources kind of in the middle with the clocks and the sequencers so the cable runs are shorter. then the envelopes, then the filters, then the osciallators.. on the lower rt. corner slap the final mixer. Effects also near the mixer since you usually send those directly over. Get some of those double plug in type patch cords too those are a huge help.