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