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