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