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