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