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