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