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