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