Looking for a job
What if you got an offer from the place you would love to work, but it’s earlier than your planned finish date? If they gave you an offer, you must have done something right. Talk to your supervisor, maybe you can have your defence sooner.
Academia
Many guides have been written about this; in short, ask your advisor.
Industry
You should start looking for a job before graduating, especially if you are a non-EU national since in that case you have a shorter window (6 months) after the PhD to find a job in Switzerland.
One good way to find a job is to do internships during your PhD, which are good anyway, since you are likely to get an offer that way. You should also ask your advisor for any contacts they have in companies you’d want to work in.
Certain companies have federal quotas for foreign citizens, which means that there are often more jobs available in January than in November or December. It also depends on the kind of job, if you want something for which a PhD is not useful it will be harder since the company will have a harder time making the case that they need your specific expertise. If you apply to a Swiss company online, you likely want to explicitly put on your CV that you are authorized to work in Switzerland, as they will ask anyway.
Of course, you can also decide to go work in another country entirely, EPFL’s name has a great reputation not just in Switzerland.