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