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