Property Graphs are similar to Concept Maps in that there is no normative style (like in UML, e.g.). The style used above is the preference of the author, so feel free to find your own style. If you communicate well with your readers, you have accomplished the necessary. page 
DOT strict digraph rankdir=LR node [style=filled fillcolor=lightyellow penwidth=3 color=black fontname="Helvetica"] HERE NODE node [style=filled fillcolor=lightblue] WHERE /^⇒/ LINKS HERE -> NODE node [style=filled fillcolor=white] HERE NODE WHERE /^⇒/ LINKS HERE -> NODE node [style=filled fillcolor=white penwidth=3 color=black] LINKS HERE -> NODE node [style=filled fillcolor=white penwidth=1 color=black] HERE NODE LINKS HERE -> NODE node [style="filled,rounded,dotted" fillcolor=white] edge [style=dotted] HERE NODE BACKLINKS NODE -> HERE