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