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