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