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)(11,17,18,13)(12,20,21,16)(19,22,24,23)(27,28)(31,32)(35,36)(38,39)(1,3,4,7)(2,5,6,8)(10,15)(11,18)(12,21)(22,23)(25,26,30,34)(27,32,28,31)(29,33,37,40)(35,39,36,38)(1,2)(3,5)(4,6)(7,8)(10,15)(13,17)(16,20)(22,23)(25,27,30,28)(26,31,34,32)(29,36,37,35)(33,39,40,38)(1,3)(2,5)(4,7)(6,8)(9,11)(10,13)(12,19)(14,18)(15,17)(16,22)(20,23)(21,24)(25,26)(27,31)(28,32)(29,33)(30,34)(35,38)(36,39)(37,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,12,14,21)(10,16,15,20)(11,19,18,24)(13,22,17,23)(25,28,30,27)(26,32,34,31)(29,36,37,35)(33,39,40,38)(9,13)(10,11)(12,22)(14,17)(15,18)(16,19)(20,24)(21,23)(25,29,30,37)(26,33,34,40)(27,35,28,36)(31,38,32,39)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.