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