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