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