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