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