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