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