It's relatively the same. Some things to note would be that if it is busy, you may need more material. At a large corporate event, I will often do two sets the whole night. Each table is far enough away that they can't hear or see what I'm doing, and I can bounce around the room.
With tables closer together, I would personally for sure use a third set if it's full and busy.
Also, a restaurant setting is a different pace than a corporate gig. For big gigs, you go from table to table non stop in order to reach every table. With restaurants (or cafe setting) you must manage tables. Some are waiting for food, some are eating, some are empty, some are ordering etc. I would typically wait until after a table had ordered, go do magic before their food came, then move on to the next table. When it was busy and all the tables are full, with only a new table every 5-10 minutes or so, then after you have hit every table, you actually have some down time.
Now a cafe, I would imagine to not be packed the whole time, and people would sit for a while. So if you have 10 tables, and you hit them all, then you are really just standing around waiting for another customer. You may end up standing around more than doing magic.
That's okay. Don't feel awkward about that. It is exactly what you are being paid for - managing customers. The exact same type of role in a restaurant would be the host/hostess. Periods of downtime, but they are being paid to be ready when a customer comes.
Being confident in this is actually important. If you are apologetic and awkward about it, then the manager will feel the same way. You want them to feel they hired a professional to manage their customer's entertainment. Your confidence helps them feel that way.
You will also have they luxury of more time with some people because you aren't rushed. However, you may also get some more "no thank you's" as many people come in for a quick coffee meeting with someone. Be prepared for that, confident in yourself in that, and provide the best customer service experience to them as you can. Thank them, wish them a terrific afternoon, and move on without being sheepish.
I'm curious to know how it goes, so post a follow up when you have a chance!