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