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