Not sure how to improve the colours. Noticed your photos have a different aspect ratio to the standard 3:4. You may have cropped them after you took them. If you've set the aspect ratio when taking the photos just bare in mind that it just crops in on the standard 3:4.
That's fine mate if that's how you like it. It's just that the camera sensor is 3:4 format. So it's just cropping in so you're just as well to crop it later.
Are you running with Scene Optimiser on in the camera settings as that will automatically boost saturation?
You can also boost it live at capture with the filter option in the camera toolbar (only when shooting at 12mp)
I would suggest instead doing it the Gallery afterwards with the edit pencil, then selecting the adjustment dial and you can select saturation in there to keep the image at full resolution eg 50/200mp.