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