I'm so last minute.
So this outfit. I wanted to reflect some of the different pieces of Saria in it-- her connection to the forest, her position as Sage, and the side of her we see in the beginning of the game versus when we see her after the Forest Temple. This is basically what I'd have her dolled up in as Sage "formal wear," more or less. Maybe traditional wear? It's organic, with the skirt like the petals of a flower, and primarily white like the Sage figures we see in Twilight Princess. It's simple, and the length to me gives it a girlish/childish quality, while the sleeves suggest a little more elegance.
She also has a simple pendant-- the Kokiri symbol carved out of Deku wood so she can take a piece of her home with her.
Also posted the original sketch so you can see how the skirt falls when she's not being all floaty: [link]