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