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