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