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