There is one secret to making wiring look neat like the two examples above, and that is to severely constrain yourself to where you can place wires.
Think of wires like cars. You can only drive your car along roads - if you take a shortcut through someone else's property they will get mad. In cites such as New York City, roads arranged in a square/rectangular grid pattern make it easy to navigate. To make your wiring look neat and easy to work on, we will follow this same virtual "road" grid pattern.
This means your wiring should only travel in straight orthogonal directions, and always make clean right angle corners*. To make corners that look good, use a very high strand count wire - in general the more strands a wire has, the more flexible it will be. The more flexible wire is, the easier it is to tame and make it travel along these "roads".
This will cause large sections of your wiring to all begin running along the same path - think of these like your trunk line "highways". Sometimes this means wires intentionally take longer paths than necessary to keep these wires on dedicated "roads", like visible in this photo of FRC 973:
But this solution only deals with the power wires - you still need to deal with the signal/PWM/sensor wires. Keeping with the same city analogy, we need to treat these as a subway or monorail and route them on a different level from the cars on the main level.
While running wires underneath a control panel might not always be feasible (especially if it is your belly pan), one idea that works really well is to build pylons using a small (#8/32 or smaller)
standoff with male thread at the top, which is screwed into small (#8/32 or smaller set screw) shaft collars. The shaft collars act as a anchor point for a small 4" zip tie, and the standoffs elevate this above the rest of your wiring. You can then bundle all your PWM/sensor wiring along this trunk line.
I don't have a good photo of this from one of 148's recent robots, so here's a quick sketch instead:
* IMPORTANT! Do not make these corners too tight, or you will strain your wire and cause increased electrical resistance. Due to V=IR causing a voltage drop, this means your motors will always receive less voltage.