Sort of like the current search function but affecting the graph view instead of displaying multiple file content matching search. Either highlight them - or even better, layout just the selected nodes (after a second or two).
Search is a bit like grep, while what I am proposing is a bit like graphing the files reported by grep -l.
A use case may be to see what other files these files are connected to!
Alternately, graph the list of files given by an external tool.
I am not sure this is at the “feature request” level though. I think a number of ideas related the graph view are worth exploring and if they are found to be really useful they may graduate to a real feature.