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