1. Yeah. 2. Strong disagree. IMHO icons in diagramming are obsolete for most purposes (smacking of UML and over-wrought database diagrams) and are likely to le

1. Yeah. 2. Strong disagree. IMHO icons in diagramming are obsolete for most purposes (smacking of UML and over-wrought database diagrams) and are likely to lead to confusion for the majority of viewers who - at best - aren't quite sure what you exactly mean in this particular case. 3. Which is what graphviz is for. It literally draws itself. Subgraphs are the groupings. 4. I would instead suggest modifying an existing graphviz .dot file, or man dot.