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