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