Lam sakipes means intentional looking, as opposed to lú which could just be passive seeing.
Less formal
Some alternate word orders allowed: Lú an myau swin swatel, An myau lú swin swatel. Not allowed: *An myau lú(n) swatel: when used in this sense, lú modifies a complete sentence, so the regular verb must be there. Definitely not allowed: *An myau lan saki (swa) swatel: lam saki does translate to "look", but it doesn't mean "look" in this sense, but rather that the cat is looking at something.
This expresses some uncertainty as to whether the cat really is black, or if it just looks that way for some reason. Because of this, the verb changes to the subjunctive (swin instead of swan).