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