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