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