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