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)(17,18)(19,20)(21,22)(23,29)(24,32)(25,26)(27,30)(28,33)(31,34)(35,36) involution — undirected(5,7,9,12)(6,10,11,8)(13,14,17,18)(15,19,20,16)(22,26)(23,30)(28,32)(31,36)(6,11)(8,10)(15,20)(16,19)(21,22)(23,29)(24,32)(25,26)(27,30)(28,33)(31,34)(35,36) involution — undirected(1,2,3,4)(5,7)(6,10)(8,11)(9,12)(13,15)(14,16)(17,20)(18,19)(21,23)(22,27)(24,31)(25,30)(26,29)(28,34)(32,35)(33,36)(5,8,9,10)(6,7,11,12)(13,16)(14,15)(17,19)(18,20)(21,24,25,33)(22,28,26,32)(23,31,30,36)(27,34,29,35)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.