A monochrome outfit, especially in a dark hue, is a little-known trick for portraying a powerful, I-can-do-this attitude at work without have to don a suit. The best way to do it is combining different textures, like she does here with a patent leather shoe, cotton pants, and a lace top.
Here is a quick guide to dress codes. The Connections Conference attire ranges from "business casual" to "business/formal". - Pretty handy advice overall, though be careful with jeans even in business casual!