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