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