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