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