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