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