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