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