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)(11,15)(12,16)(13,14)(17,20)(18,22)(19,21)(23,24)(25,26,30,34)(27,31,29,32)(28,36,37,33)(35,40,38,39)(3,7)(5,8)(10,14)(15,20)(16,21)(22,24)(25,27,30,29)(26,31,34,32)(28,35,37,38)(33,39,36,40)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,18)(13,17)(14,20)(16,22)(19,23)(21,24)(26,32)(27,29)(28,37)(31,34)(33,39)(36,40) involution — undirected(2,6)(3,7)(11,17)(15,20)(18,23)(22,24)(25,28)(26,33)(27,35)(29,38)(30,37)(31,39)(32,40)(34,36) involution — undirected(9,12,13,19)(10,16,14,21)(11,18,17,23)(15,22,20,24)(28,37)(33,36)(35,38)(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.