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