Is it me or why do I never see anyone take these drawings down to the port level? Showing that this cable is plugged into port x and that cable is plugged into port Y of that device? I guess it depends on what you need it for / who's going to use that. I do my drawing religously that way and never see anyone do that : ( (partly for me to really document the details of the network and partly for users that might get in there, unplug a cable, reconnect somewhere else and swear that they put it back where it was originally : )
A site I used to look at was
http://www.ratemynetworkdiagram.com