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