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