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