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