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