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