In the trade, typically the rule of thumb is to isolate line voltage from low voltage. If possible, a foot apart is what we aim for, may not work in a home setup, just giving you my expertise. Keeping data/signal wires together, and keeping anything 120v together is the trick.
As for the picture, it looks like they're just showing an example, not what you should do. I wouldn't have serial and 3.5mm in the same pocket as line voltage if you want best possible results, my 2¢.