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