One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6,8,12,9,11,17,19)(7,13,14,18,15,20,16,10)(2,4)(21,22)(23,30)(24,28)(25,33)(26,29)(27,31)(32,35)(34,36) involution — undirected(5,7,9,15)(6,10,11,18)(8,16,17,14)(12,20,19,13)(21,23)(22,27)(24,31)(25,34)(26,32)(28,35)(29,36)(30,33)(2,4)(6,11)(10,18)(12,19)(13,20)(21,24,26,25)(22,28,29,33)(23,31,32,34)(27,35,36,30)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.