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