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