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