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