I'm not aware of a book about this specifically, but almost all of our grammar terminology, at least when it comes to Greek and Latin specifically, is due to a (short!) work ascribed to Dionysius Thrax, Τέχνη Γραμματική ('The Art of Grammar'), filtered through the sometimes questionable translation skills of Roman grammarians, and from there lifted almost unchanged into English.
A famous story there is how the accusative got its name: Thrax named it the αἰτιατική (literally 'causal', from αἰτιατός 'caused' and the suffix -ικός, I guess because he saw the direct object as being caused by the verb), which some Roman grammarian (traditionally Quintus Remmius Palaemon, who was very influential in his time, though his grammar has not come down to us) interpreted as instead deriving from αἰτιάομαι 'accuse' and the suffix -τικός, calquing it as accūsātīvus.
This is a funny goof, but most terms are effectively calques of Thrax like that, and many of them more successful than that one.
For your specific example, English conjugation is from Latin coniugātiō, which faithfully calques Thrax's συζυγία, literally 'yoking together'. An etymological dictionary (like Wiktionary) will usually give you the Latin and Greek terms, with or without the biographical details—if a Greek word is given, you can almost be certain it's due to Thrax.