One of the meanings of cool
(source: Oxford Dictionary) is "informal - fashionably attractive or impressive."
So, my thinking is that ''cool-beauty" could be translated into "de uma beleza (visualmente) atraente", that can be used to refer to people (usually in the sense of the original beauty
of the young, the uncorrupted, the one in his original condition of purity).
It looks like we would think of cool-beauty a Japanese girls with their "narrow eyes", and they in their turn, may think that cool-beauty is to a have a western look, with bigger eyes. Just see the make up cool-beauty vs Japanese idol athttp://www.yuhjiun09.com/2014_07_01_archive.html
In both cases, the "cool-beauty" appearance suggested would be that of younger/more original or trying to remain more in in tune of her teen ages, sort of.
a scenario would be "pristine" like this http://img.phombo.com/img1/photocombo/1 ... 891944.jpg
As for products, it certainly would be visually attractive, a must-have. One could think of it as "cute" (fofo/fofinho etc...), for instance to talk about a mobile phone features etc...
In time: it´s from my impressions, others may chime in and say otherwise, or in a slightly different way. Let´s wait for more, then.