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