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