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)(25,26,32,35,31,27,30,29)(28,34,40,39,37,33,38,36)(1,3,4,8)(2,5,6,7)(9,10,13,16)(11,17,18,14)(12,21,20,15)(19,22,24,23)(25,27,31,26)(28,33,37,34)(29,32,35,30)(36,40,39,38)(2,6)(5,7)(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,24)(21,23)(25,28)(26,33)(27,34)(29,39)(30,38)(31,37)(32,40)(35,36) involution — undirected(3,8)(5,7)(11,18)(14,17)(19,24)(22,23)(25,29,30,27,31,35,32,26)(28,36,38,33,37,39,40,34)(9,12,13,20)(10,15,16,21)(11,19,18,24)(14,22,17,23)(26,27)(28,37)(29,35)(38,40)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.