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