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