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