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