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