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