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