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