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