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)(25,26,30,33,31,34,29,32)(27,28,35,38,37,39,36,40)(1,3,5,4)(2,6,8,7)(9,10,13,14)(11,17,19,15)(12,16,20,21)(18,23,24,22)(25,27)(26,28)(29,36)(30,35)(31,37)(32,40)(33,38)(34,39)(1,3,5,4)(2,7,8,6)(9,11,13,19)(10,15,14,17)(12,18,20,24)(16,22,21,23)(25,28)(26,27)(29,38)(30,40)(31,39)(32,35)(33,36)(34,37)(1,4,5,3)(2,6,8,7)(12,20)(16,21)(18,24)(22,23)(25,29,31,30)(26,32,34,33)(27,35,37,36)(28,38,39,40)(9,12,13,20)(10,16,14,21)(11,18,19,24)(15,22,17,23)(25,29,31,30)(26,33,34,32)(27,36,37,35)(28,38,39,40)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.