It's hard to get extract beers as light in color as you'd like. Even if you use "extra light" extracts. Seems you can do better with dry malt extract than liquid, but the color isn't going to be as light as if you just mashed a low-kilned malt yourself. Since you're already using extra-light DME, not sure how much lighter you can go.
The color is coming from the malt, so subbing out DME for other stuff like rice syrup, will lighten the color.
Be careful in how hard and long you boil; those can develop additional color. If you can do a full boil rather than a concentrated boil, that helps.