Some surveys allow you to view a visual summary of the responses from others. However, if a survey is marked as anonymous, and only one response has been completed, it will not show the responses to anyone. 

Some surveys only show the responses to users with elevated priveleges, such as users with the 'Mentor' role. When you click on the activity, you will see instructions which will explain whether or not you have permission to view the survey responses.

If you are a mentor and would like to access survey responses for your group, simply click on the activity link, then click the 'Analysis' tab which will appear. Refer to the screenshot attached. 

If the survey is anonymous, mentors will still only see a summary of responses and will not see any names associated with the responses.