Ellos=male
Ellas=female

Ellos/Ellas tienen una apariencia, hablan y se comportan de una manera diferente a la nuestra.

Greetings from: Oso ¶:^)

then the full sentence translated is: Ellos lucen, hablan y actúan diferente de/a nosotros.-
good luck

la traduccion seria esta:
Ellos se ven,hablan,y actuan diferente de nosotros.
Xicla

As you can see the gender of both of the pronouns in this sentence depends on who you are talking about. If "they" and "us" consists of a group of males, or a group of males and females you must use "ellos" and "nosotros," even if there is only one male in the group and the rest are female. If the group is all female you can only use "ellas" or "nosotras."
Use which ever case applies.

The verb most commonly used in Spain, and in Latin America as well, to refer to how someone looks is "verse." The verb "lucir" connotates that someone looks good or has a glow to them.

The most adequate verb to refer to someone's behavior is "comportarse."
"Actuar" is okay but usually refers to theatrical acting.