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