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