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