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