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