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