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