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