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