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