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