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