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