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