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