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