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