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