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