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