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