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