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