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