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