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