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