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