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)(27,34)(28,31)(29,35)(30,33)(32,38)(36,39)(37,40) 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)(26,32)(28,34)(29,36)(30,37)(31,38)(33,39)(35,40)(1,3,4,7)(2,6,5,8)(10,14)(15,20)(16,21)(22,24)(25,28,31,26)(27,34,38,32)(29,35,30,33)(36,40,37,39)(9,11,13,18)(10,15,14,20)(12,17,19,23)(16,22,21,24)(25,29,31,30)(26,33,28,35)(27,36,38,37)(32,39,34,40)(9,10)(11,15)(12,16)(13,14)(17,22)(18,20)(19,21)(23,24)(25,27)(26,34)(28,32)(29,36)(30,37)(31,38)(33,40)(35,39) involution — undirected(9,12)(10,16)(11,17)(13,19)(14,21)(15,22)(18,23)(20,24)(25,30,31,29)(26,35,28,33)(27,37,38,36)(32,40,34,39)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.