I really, really like the 9th at Black Sheep. Illustrations of hugging the bunker left gives you a much shorter, flatter approach to a more open green, while using the considerable width to the center and right of the fairway will be safe, but cost you distance hitting into the upslope and leave a more dramatically uphill shot over bunkers.
Actually, the 2nd a Black Sheep would also make a good "diagram" hole. Lay up to bunker or challenge the shoot off the tee to make it reachable? Play safe right of the bunker to leave uphill third shot, or over the bunker to leave flat pitch.
Four at Flossmoor would be good as well. So is 8 at Highlands of Elgin. Olympia Fields (both courses) and Medinah ask you to execute shots more than make strategic decisions on both courses, IMO, or at least make decisions in ways that can be illustrated.
I assume you'd like to use a more "name" course for this illustration however.