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