It so happens, I m re-reading the book as it is my "bible" of trading. How about his Tandem Trading? How about following the leaders? He kept his own detailed records, in effect, creating his own indicators. I know what you mean, just don't want people to take it literally. All the answers given so far have validity imho. However, transaction costs have fallen drastically and as long as you practice patience, there's nothing wrong applying his methods intra-day. It's easy to say "oh the big money is with the big moves," but not so easy to make a living capturing them. I don't think Livermore would be able to do that if he didn't make his initial stake from day trading the bucket shops.
I haven't read the book you mention but I have read Reminiscences of a Stock Operator and in that he definitely day-traded (as well as longer term positions) himself. Perhaps he felt with his experience and feel for reading the tape he could - but the public shouldn't.