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