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