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