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