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