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