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