BOSTON (Reuters) – Skyhigh Networks, a company that helps businesses secure data that employees access through Internet sites and cloud-computing services, said on Monday it has raised $40 million in financing in a Series C round led by Greylock Partners and Sequoia. That brings the total capital raised to date by the Cupertino, California-based company to $66.5 million. Skyhigh, which was launched in February 2013, offers a service that allows a company to monitor and secure access to a wide variety of Internet sites and cloud-computing services including Google Inc, Salesforce. …