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