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