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