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