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