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