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