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