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