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