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