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