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