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