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