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