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