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