There are so many different ways to approach case law research. Here are a few suggestions:

• In an annotated statutory code, use case the citations given for the employment discrimination statutes.
• Use citations given in a secondary source such as a relevant American Law Reports article or a legal encyclopedia. 
• Run a keyword search in Westlaw or Lexis or Bloomberg Law. Bloomberg is especially good for employment and discrimination law because it owns the content produced by BNA (Bureau of National Affairs).
• Run a search within the Employment topic in the big three .
• Use the Key Number system (topic: Civil Rights, many relevant key numbers) in Westlaw. 
• You can even use Google Scholar to search for case law, but you'll still want to use Shepard's or KeyCite or BCite to update.