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