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