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