I have an LP with this song, sung by the great Germaine Montero. The translation on the sleeve:

Los Quatro Muleros

Of the four mule drivers,
My Mother, the ones who go for water,
The one with the gray mule
Has stolen my heart.

Of the four mule drivers,
My Mother, the ones who go to the river,
The one with the gray mule
My Mother, is my husband.

Why do you look for lighting
for your house, up and down the street,
When in his soft face,
My Mother, there are live coals?

The last verse is:
Ya que tu casa alumbre,
mamita mia,
La calle abajo, la calle arriba,
Si de tu cara sale,
Mamita mia,
la brasa viva.
(From Andalusia)