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