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