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