Angel Giraldez paints most, if not all, of the studio's models. He has
a blog that occasionally has tutorials or at least lists the paints used. His paintjobs have as much to do with application technique as color selection, though, so the frequently brief explanations may not be all that useful to you, depending on your style and level of experience.
There's also a P&M blog on Dakka, although I can't remember the name of the thread or poster (terribly helpful, I know...). If you can find it, though, there are some great step-by-steps of Ariadnan models. Again, not exactly "basecoat, wash, drybrush, and done" tutorials, so it may or may not prove particularly useful. Great inspiration, though, at the very least.
In more general terms, I do have one piece of advice - slightly desaturated colors tend to look best on Ariadna models, in keeping with the camo/modern military theme. Paints like Vallejo Model Color, which are geared towards historical/military painters, work nicely. Having only
GC/VGC colors, myself, I had to tone down even my Haqqislam greens to get them where I wanted (
roughly approximating the box art), using touches of appropriately dark or light browns and beiges.