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