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