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