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