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