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