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