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