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