How do I ask to draft recommendation letters for my references?
Short of asking to draft the letter (which many letter writers consider inappropriate), you can simply ask the letter writer to address particular issues in your letter.   You should also supply copies of your resume, academic transcripts, and any statement of purpose that you've written so that the letter writer can tailor the letter to support your application.  

For example, you might say something like (to your industry professional), "I think that your letter could help by commenting on my work habits and skills in software development.  As you can see, I'm particularly interested in doing a dissertation related to machine learning, so you might also address my experience in machine learning at XYZ corp."