Check out this graphic from Sunday's NY Times, about seamy goings-on in Washington:
Wow! There is a lot of information on the page (maybe too much).
The widely recognized master of these kinds of network-storytelling pictures was Mark Lombardi (1951-2000), who elevated these diagrams to an art form. See here for some selections of Lombardi's work, like this one:
You can also read a critical overview of Lombardi's life and work here.