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