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