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