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