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