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