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