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