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