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