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