I am trying to find the earliest use of plane diagrams of various shapes for representing sets. For example, this is snapshot is from the book called Some Modern Mathematics for Physicists and Other Outsiders; An Introduction to Algebra, Topology, and Functional Analysis by Roman, Paul (1974).
Another common example, is that of representing convex sets which all over the web:
Note that the use of circles in logical discussions is several centuries years old (1690, as found by SE reader (Mauro Allegranza) in Google Books. This is in Latin Book Image.
This is from Nicolas Bourbaki, Elements of Mathematics, General Topology Chapters 1-4, Translated