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)(11,21)(13,16)(15,29)(18,33)(20,26)(22,35)(23,37)(24,39)(25,38)(27,28)(30,31)(32,36)(34,40) involution — undirected(1,3)(2,5)(4,8)(6,7)(9,10,14,17)(11,22,25,18)(12,16,19,13)(15,20,28,32)(21,33,38,35)(23,24,34,31)(26,29,36,27)(30,40,39,37)(9,11)(10,18)(12,23)(13,24)(14,25)(15,30)(16,31)(17,22)(19,34)(20,37)(21,29)(26,33)(27,38)(28,39)(32,40)(35,36) involution — undirected(3,8)(5,7)(9,12,14,19)(10,13,17,16)(11,23,25,34)(15,26,28,36)(18,24,22,31)(20,27,32,29)(21,37,38,40)(30,33,39,35)(2,6)(5,7)(9,13,14,16)(10,19,17,12)(11,24,25,31)(15,27,28,29)(18,34,22,23)(20,36,32,26)(21,30,38,39)(33,37,35,40)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.