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