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