The general advice I've given to students in the past, is to have one prepared, offer to present it, but don't necessarily assume the examiners will approve or request it.
It's better, if you're given the opportunity, to present your work and subsequently frame the argument in your terms. I've never actually seen examiners refuse the offer of a presentation, as it's typically helpful for all concerned.
The avoidable situation you don't want to be in, is to go into the viva with no presentation ready, and be immediately asked 'so would you like to present your work before we start?' because, if the answer is 'I didn't prepare anything', it doesn't exactly look like you've put 110% into your viva prep.
It's entirely up to the examiners if they want to allow you to present, but it is very much the norm, and whilst having no presentation should - in theory - have little bearing on the viva outcome, as I mentioned, to not be ready to present your research formally going into one can look bad if you're asked to do it and can't.