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