I read the specs for your camera. Since it does not have RAW capability, which is important for non-strobe shots, you will have to use some different methods. The camera also does not have any manual settings such as Tv, Av and M so you have to use the "P" or "Auto" shooting modes. Try both and compare.
1. For your internal strobe (flash) shots experiment with a White Balance of "Auto", "Daylight" and "Cloudy". The "Cloudy" setting usually produces softer colors. The ISO of 100 is the lowest setting for that camera so try to stay with that for strobe shots. You will have to experiment with how close you can get to a subject and still get even lighting with the internal flash.
2. For your non-strobe shots:
Option A: Use the "Custom" White Balance. That requires you to calibrate your white balance off a white slate or card while underwater and at varying depths as visibility and ambient light conditions change. The ISO of 100 will likely have to be increased as the amount of ambient light at depth is reduced. Stay at ISO of 400 or less as higher settings will increase the amount of "digital noise" in the photo. Even the 400 setting may produce digital noise. Experiment with that.
Option B: If you use "Auto" white balance on non-strobe shots you will get bluish photos which can be adjusted to some degree in Photoshop with a process called "underwater" which can be downloaded
HERE as an Action file which you have to load into Photoshop.
Option C: Purchase an externally mounted red filter which you can thread on when shooting non-strobe shots. The red filter works best at shallower depths. The best feature of a red filter is for shooting videos at shallower depths. The Ikelite filter for your housing is
HERE.