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