One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(4,6)(7,8)(9,11)(10,18)(12,13)(14,17)(15,21)(16,22)(19,20)(23,24,28,31)(25,26,29,34)(27,30,36,38)(32,33,35,37)(8,13)(11,14)(15,18)(20,22)(23,25,28,29)(24,26,31,34)(27,35,36,32)(30,37,38,33)(3,4,5,6)(7,9)(8,14)(10,19)(11,13)(12,17)(15,20)(16,21)(18,22)(23,25)(24,26)(27,32)(28,29)(30,33)(31,34)(35,36)(37,38)(7,10,12,21)(8,15,13,18)(9,16,17,19)(11,20,14,22)(23,26)(24,29)(25,31)(27,33)(28,34)(30,35)(32,38)(36,37)(7,11,12,14)(8,9,13,17)(10,20,21,22)(15,16,18,19)(23,27,28,36)(24,30,31,38)(25,32,29,35)(26,33,34,37)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.