How to tell my advisor that I am quitting my PhD and what to say to an employer about why I am leaving
This is pretty common in my field (applied math). Students see the amount of money they can be making, and see the amount of work a PhD is, and leave. Be cordial about it, but the institution (and potential adviser) will likely be very unhappy. Make sure you are confident in your choice before even mentioning it to your adviser. Because of this being a common issue, I know that for plenty of professors the moment you start speaking about industry you have already burned the bridge.

As for what people in industry will think, I can't comment for them. Some will probably think you made a good conscious choice to not continue pursuing a PhD (just tell people about how the job market isn't that good). Others will think you dropped out.

This is just such a personal thing. People will see it how they want to see it no matter how you tell the story.