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