This is a male oriental garden lizard, which is also known as changeable lizard. Belongs to the family of agamidae.
The photo was clicked at the point of dondra (near the survey point plaque; the southmost point of Sri Lanka) making it possible that this is the lizard that lives southmost of all the lizards of Sri Lanka. Another male lizard and a baby lizard were found at the same place (on 4thMarch 2017), but was unable to find the female lizard.
Observe the well grown limbs of this lizard which is a key characteristics of the agamids.
A sincere thank to @thisarug for identification.