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