First off, get a big piece or cardboard or some visqueen and put it down before you start. Next, get a big drain pan, or two smaller ones.
Sometimes messes can't be avoided. So, when you do make a mess, clean up the "india ink" diesel oil as quick as you can. I like the combination of brake cleaner and hand cleaner to get up as much of the immediate mess as possible. Pressure washing with strong degreaser and/or muratic acid will clean concrete, albeit at the expense of the concrete surface long term. Sealing my garage floor was the best thing I ever did, now any dirt/grease/oil is easily cleaned.
Good luck, and may the cleaning force guide you to a cleaner future.