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