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