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