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