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