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