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