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