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