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