One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10)(11,18)(12,16)(13,22)(14,17)(15,21)(19,24)(20,23)(25,26,30,32)(27,29,34,35)(28,36,38,31)(33,37,40,39)(9,11)(10,15)(12,19)(13,20)(14,21)(16,23)(17,18)(22,24)(25,27)(26,29)(28,37)(30,34)(31,33)(32,35)(36,40)(38,39) involution — undirected(2,5)(6,8)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,18,24)(25,28,32,36,30,38,26,31)(27,33,29,39,34,40,35,37)(9,13,14,12)(10,16,17,22)(11,20,21,19)(15,23,18,24)(28,38)(31,36)(33,40)(37,39)(1,3,4,7)(2,6,5,8)(11,21)(15,18)(19,20)(23,24)(25,29,32,34,30,35,26,27)(28,37,36,33,38,39,31,40)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.