There you go, thinking in terms of D&D alignments, again!
I think that D&D closest approximation of the character of far realms beings is indeed evil, because their interactions are automatically antithetical, in a "collateral damage" sort of way. However, taken to their logical conclusion (logic applied to Far Realms beings! Now that's a stretch) the Lovecraft-inspired Far Realm would not seek to dominate, it would simply seek to exist, thrive, awaken, what have you, and the very activities would result in death. From D&D perspective, their actions are evil; but they aren't evil outside of the D&D term. They're as evil as a human killing the ants that he trods over; I'm not even sure they acknowledge other beings as "sentient".
But I think someone creating a Far Realms NPC who is in the traditional mustache-twirling evil mould would be doing it a disservice. It's more in a Cthulhu "why won't my damned alarm clock go off?" frame of thinking.