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