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