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