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