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