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