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