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