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