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