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