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