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