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