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