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