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