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