I applied for a group visa to the Swiss Embassy. The group consisted of 49 students and 4 chaperones. Unfortunately, all students' visas were rejected and all of the chaperones got their visas. Can I now travel on my visa individually, without the group? I had been to Spain and Italy last year, but that was also on group visa.
In theory, yes, as long as you have a valid visa, you may travel to Switzerland. In practice, however, you may have issues entering the country.
Your stated premise has changed considerably from when you submitted your visa application and, instead of a group of more than 50 and the original purpose of the visit, you are a sole traveller with an entirely different itinerary.
You may be allowed entry, but it may not be worth the risk and expense should you be turned away. With your favorable history of visa issuance by Spain, Italy, and Switzerland, it may be preferable to apply for a visa for your solo trip.