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