Here's how you can do that.
I think the nature of the site will force you to use the citation format that leaves out the author's name, since most of the contributors don't go by their full names here.
I found some interesting articles on this issue on the APA website, check it out:
This first one allows you to cite website material that has no author, no year, or no page number. This is not the best match you can find because Socratic answers do provide a year, despite the fact that you don't have actual authors and page numbers.
Another option is
This focuses solely on the fact that you have no author, so it could work better.
You can also cite an entire website
I think this could also work for Socratic references.
Don't forget about using a retrieval date, since Socratic answers can change at any time via updates.
Other useful links:
the last one actually helps you generate an APA format citation, so that could be useful if other approaches fail.