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