This picture covers the House of Finwë so it would mostly consist of the Noldor elves who lived in Valinor. Since Legolas is descended only from the Sindar and did not marry into the House of Finwë as Elwing, Eol or Celeborn did, he is not included in this version of the image.
However, this is a work in progress. It's possible that the artist will eventually include the household of Thingol, who ruled the Sindar, in which case Legolas, his father Thranduil, and Thranduil's father Oropher could be included in the picture. The only issue with that is Oropher is only given as "kin of Thingol", but nowhere does it state how they were related.