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