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