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