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