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)(11,16,12,17)(13,23,24,14)(19,20,21,22)(25,26,31,30)(27,32,36,35)(28,37,39,33)(29,40,38,34)(3,7)(5,8)(9,11,15,12)(10,16,18,17)(13,19,24,21)(14,22,23,20)(26,30)(32,35)(33,37)(34,40)(1,2)(3,5)(4,6)(7,8)(11,12)(16,17)(19,21)(20,22)(25,27,31,36)(26,32,30,35)(28,38,39,29)(33,40,37,34)(9,12,15,11)(10,17,18,16)(13,19,24,21)(14,22,23,20)(25,28,31,39)(26,33,30,37)(27,29,36,38)(32,34,35,40)(1,3)(2,5)(4,7)(6,8)(9,13)(10,14)(11,19)(12,21)(15,24)(16,22)(17,20)(18,23)(25,29)(26,34)(27,28)(30,40)(31,38)(32,33)(35,37)(36,39) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,14)(10,13)(11,20)(12,22)(15,23)(16,21)(17,19)(18,24)(25,30,31,26)(27,35,36,32)(28,37,39,33)(29,40,38,34)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.