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