depfun() listed the paths of all files a specific m-file (or p-file) needed to function. It didn't produce a graph, unless you're refering to a different 3rd party function.
If you're trying to list the matlab files and toolboxes required to run a specified function, use matlab.codetools.requiredFilesAndProducts()
Example
[funcList, toolList] = matlab.codetools.requiredFilesAndProducts('MyFunction.m');
funcList' %this lists all function dependencies
{toolList.Name}' %this lists any toolbox/product dependencies
{toolList.Version}' %this lists toolbox/product version numbers
