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