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