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