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