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