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