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