If you have Visio or other similar application that helps.
Another way to make them presentable on paper is to use graphviz dot
Visio is faster, but proprietary, however you can save in many formats including SVG.
Dot is widely known an used and is what I used here. The dot output was saved as SVG which is nice because Internet browsers can read them and they scale nicely.
Both have a learning curve, but once you do it for a while it becomes old hat
You might want to search the SWI-Prolog packages, several of them make use of GraphViz, e.g.
http://www.swi-prolog.org/pack/list?p=gvterm
and might actually do what you are planing or at least have code that use to work but is no longer maintained, but is useful for studying.