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