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