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)(28,29,34,31)(36,39,40,38)(1,2)(3,7)(4,6)(5,8)(10,14)(12,19)(15,20)(18,23)(25,27,30,37)(26,32,33,35)(28,36,34,40)(29,38,31,39)(1,3)(2,5)(4,8)(6,7)(9,11)(10,15)(12,18)(13,17)(14,20)(16,22)(19,23)(21,24)(25,28,31,26,30,34,29,33)(27,36,39,32,37,40,38,35)(3,8)(5,7)(10,14)(11,17)(16,21)(18,23)(26,33)(27,37)(28,34)(38,39) 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)(26,34,33,28)(27,38,37,39)(32,40,35,36)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.