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