I have noticed that CMYK colors can look a lot brighter and more saturated on the iPad than they do on the desktop - they look more like RGB colors. Are you using global swatches from Pantone color books, like the Color Bridge guide? Or are you mixing colors with the sliders?
When I use swatches or color formulas from a Pantone guide I'm happy that the swatches, numbers and formulas are consistent from iPad to desktop, but I think the difference in what you see might just be because they are 2 different screens. The iPad doesn't seem to use color profiles - file info shows "untagged CMYK" so there's not a matching color profile you could use on the desktop, other than "don't color manage". I'm not 100% sure about this, but that's how it looks to me.
I would lean towards using RGB on the iPad and then convert it on the desktop - or - use CMYK swatches and formulas you can check in a Pantone book if you have to use CMYK on the iPad, and live with the fact that it is going to look different on screen than it will when printed.