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