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