Lets give the artist a bit of a break.
Is the image lously? Yup. Should a bit of artistic leeway be allowed? Perhaps.
But underwater and underway photos of USN subs are, shall we say, somewhat hard to get. Besides, submarines in service are usually slimy, ugly looking things at best. Most models I've seen of submarines show the hull number and hatch markings and a clean, nice hull. I'm not surprised that the book's cover would be illustrated that way.
A more accurate image could have been used by the Squadron folks for a book that is intended for modelers to use as an accurate source, but I believe it wouldn't have been an interesting enough looking cover to attract book sales.
Just like the threads awhile back on box art, the line between accuracy to the model, or prototype, and an exciting, sales grabbing image, will always be a bit blurred, at best.