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