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)(27,30)(28,33)(29,34)(31,36)(32,37)(35,38)(39,40)(1,2,5,4)(3,6,7,8)(9,11,14,13)(10,12,16,15)(18,22)(23,24)(26,27)(31,33)(32,34)(38,39)(9,12,14,15)(10,11,16,13)(17,18)(19,23)(20,24)(21,22)(25,27,30,26)(28,31,36,33)(29,34,37,32)(35,38,40,39)(1,3)(2,6)(4,8)(5,7)(9,10)(11,12)(13,15)(14,16)(17,19,21,20)(18,23,22,24)(25,28,30,36)(26,31,27,33)(29,35,37,40)(32,38,34,39)(1,4,5,2)(3,8,7,6)(9,13,14,11)(10,15,16,12)(17,20,21,19)(18,24,22,23)(25,29)(26,32)(27,34)(28,35)(30,37)(31,38)(33,39)(36,40)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.