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