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