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