Actually, her wreck site was discovered in 2019; it is said that it was found 50 nautical miles from Okinawa and was confirmed by the Navy.

Also, you have the wrong photo. That is not the WW2 USS Grayback. The photo you have is of the USS Grayback (SSG-574), which was a Grayback-class submarine. It was launched in 1957 and decommissioned in in 1984.

The one you're talking about is SS-208, which was a Tambor-class submarine.