This article from Harvard Business Review by Todd L. Pittinsky posits that traditional diversity arguments have not convinced Silicon Valley about diversity's value because Silicon Valley is among the most innovative in technology while remaining the least diverse.
This article from McKinsey & Company by Vivian Hunt reports on the research which says that companies with greater diversity have greater financial returns.
This article by Shana Lebowitz describes the results of a MIT and Georgetown study which found that, despite being happier when working with people of the same gender, gender-diverse teams were more productive.