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