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