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