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