The two most obvious things about Dame Edna are her purple hair and big blingy glasses. It looks like she is wearing a medium blue shadow, a whole lot of reddish brown blush and bright red lipstick.
Dame Edna typically wears some type of reddish lipstick - sometimes a true red, sometimes with a purple tinge to it. As Dalylah mentioned lots of blush and lots of blue eyeshadow - her look is very retro 80s in terms of color.