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)(11,15)(12,24)(13,23)(14,20)(16,19)(17,21)(18,28)(22,29)(25,34)(26,35)(27,37)(30,32)(31,38)(33,40)(36,39) involution — undirected(2,5)(6,8)(9,11,15,10,17,20,14,21)(12,25,28,36,29,35,27,40)(13,23,30,19,31,38,16,32)(18,34,24,33,37,26,22,39)(1,3,4,7)(2,6,5,8)(9,12,15,28,17,29,14,27)(10,18,20,24,21,37,11,22)(13,26,30,39,31,34,16,33)(19,35,38,40,32,25,23,36)(2,5)(6,8)(9,13,15,30,17,31,14,16)(10,19,20,38,21,32,11,23)(12,26,28,39,29,34,27,33)(18,35,24,40,37,25,22,36)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.