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