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)(27,31)(28,36)(29,30)(32,38)(33,34)(35,40)(37,39)(9,11,12,15)(10,13,14,16)(17,18,21,22)(19,20,23,24)(26,30)(27,33)(32,36)(35,37)(10,14)(13,16)(18,22)(19,23)(25,27,29,33)(26,31,30,34)(28,37,38,35)(32,40,36,39)(1,2)(3,6)(4,5)(7,8)(9,10)(11,13)(12,14)(15,16)(17,19)(18,20)(21,23)(22,24)(25,26)(27,34)(28,32)(29,30)(31,33)(35,40)(36,38)(37,39) involution — undirected(1,3,4,7)(2,6,5,8)(9,11)(10,13)(12,15)(14,16)(17,20)(18,19)(21,24)(22,23)(25,28)(26,32)(27,35)(29,38)(30,36)(31,39)(33,37)(34,40)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.