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