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)(11,21)(12,18)(13,15)(14,19)(16,20)(17,23)(22,24)(26,31)(28,35)(33,40)(36,38)(3,7)(5,8)(9,11)(10,17)(12,14)(13,22)(15,19)(16,23)(18,24)(20,21)(26,31)(27,32)(33,40)(34,37) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,12,16,13)(10,18,20,15)(11,14,23,22)(17,24,21,19)(25,26,30,31)(27,28,32,35)(29,33,39,40)(34,36,37,38)(1,3,4,7)(2,5,6,8)(9,13,16,12)(10,18,20,15)(11,22,23,14)(17,24,21,19)(25,27,30,32)(26,28,31,35)(29,37,39,34)(33,38,40,36)(1,2)(3,5)(4,6)(7,8)(9,14,16,22)(10,19,20,24)(11,12,23,13)(15,21,18,17)(25,28)(26,32)(27,31)(29,38)(30,35)(33,34)(36,39)(37,40)(9,15,16,18)(10,13,20,12)(11,19,23,24)(14,17,22,21)(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.