We don't have synonyms for gray power yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are grey power, gay power and great power.
(n) :
(chiefly US) Alternative form of grey power. [(chiefly UK, Canada, Australia, idiomatic) The collective political, economic, and social influence of senior citizens, especially when they are mobilized by a common interest.]
(n) :
(chiefly US) Alternative form of grey power. [(chiefly UK, Canada, Australia, idiomatic) The collective political, economic, and social influence of senior citizens, especially when they are mobilized by a common interest.]