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