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