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