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