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