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