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