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