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