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