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