The Moodle has a log table where all access to course's pages are logged. These can be queried and the activity of a given student can be viewed in a graph.
But maybe it could be interesting to have a graphical view of the activity in a course, which are the activities more visited, form where, the user moves....
Well, i did a sample with 2 resources and 1 quiz...
You might be interested in Christian Milani's "gismo" - there are some screen captures here, and it's discussed in this thread.
There are a number of open source weblog mining tools out there which could produce the network view you're looking for, but I don't know of any that have been integrated into Moodle (yet).