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