Here is a delighful short documentary by the BBC on the Tube Map. The breakthrough in its design by Harry Beck is that it focused not on the reality of the geography - that is so complex - but on making the links and connections very clear. You as a travellor always know where to go and how to get there. Here is a nice link to more information.
Here is the 1933 Map
As I watched this I started to wonder about whether this principle might apply to mapping social networks?
What do you thinK?