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)(11,19)(12,23)(13,27)(14,18)(15,21)(16,25)(17,29)(20,34)(22,33)(24,38)(26,32)(28,31)(30,35)(36,39)(37,40) involution — undirected(9,11)(10,15)(12,24)(13,28)(14,22)(16,30)(17,33)(18,31)(19,27)(20,25)(21,29)(23,36)(26,35)(32,38)(34,37)(39,40) involution — undirected(2,6)(3,4)(7,8)(9,12,13,26,14,25,29,40)(10,16,17,32,18,23,27,37)(11,20,21,35,22,24,28,39)(15,30,19,34,31,36,33,38)(1,3,5,4)(2,7,8,6)(12,25)(16,23)(20,24)(26,40)(30,36)(32,37)(34,38)(35,39)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.