One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(5,6)(7,16)(8,21)(9,26)(10,14)(11,15)(12,18)(13,24)(17,32)(19,28)(20,31)(22,27)(23,30)(25,35)(29,34)(33,36) involution — undirected(5,7,11,20)(6,12,15,28)(8,22,24,33)(9,19,10,18)(13,29,21,32)(14,31,26,16)(17,23,34,25)(27,35,36,30)(5,8,9,23,11,24,10,25)(6,13,14,30,15,21,26,35)(7,17,18,33,20,34,19,22)(12,27,16,29,28,36,31,32)(1,2,3,4)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.