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