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