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