How do I ask to draft recommendation letters for my references? My references for my graduate program applications include an adjunct professor and an industry professional (both not very academic) and I am not sure if they really have time to invest in writing the recommendations for me, although I am pretty sure they will write for me if I asked them to. 

I heard that often time the reference would ask the students to draft the letter before they even edit and send away online because they are usually busy and really don't give a damn on your application or simply because they haven't written any recommendation before. So I wonder if it is okay to just ask in the first place something like "I can also draft the letters for you if you don't have time (Are there better ways to express this request?)" when I reach out to my references to write the recommendations for me? 

Another good thing about this is I can basically write in a way that includes what I think the admission committee would consider valuable in my letter. I mean, after all, I know about my program much better than my references, and I know how to better phrase my experience to make them relevant.
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."