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