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