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