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