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