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