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