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