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)(11,16)(12,15)(13,14)(17,18,21,20)(19,22,23,24)(26,30)(28,35)(31,36)(34,39)(1,3,6,8)(2,7,4,5)(10,14)(12,16)(19,23)(22,24)(27,33)(31,36)(34,39)(38,40)(2,4)(3,8)(9,11,13,15)(10,12,14,16)(17,19,21,23)(18,22,20,24)(25,26)(27,31)(28,32)(29,30)(33,36)(34,38)(35,37)(39,40)(1,4,6,2)(3,7,8,5)(9,12,13,16)(10,15,14,11)(17,18,21,20)(19,22,23,24)(25,27,29,33)(26,31,30,36)(28,34,35,39)(32,38,37,40)(1,5,6,7)(2,3,4,8)(9,10)(11,12)(13,14)(15,16)(17,20,21,18)(19,24,23,22)(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.