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