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