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