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