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