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