It’s not clear where or when the Tequila Sunrise cocktail first saw light of day, but it does date to at least 1940—earlier than the Margarita.
 
 
Wikipedia: Tequila Sunrise (cocktail)
The Tequila Sunrise is a cocktail so named for the way it looks when it is poured into a glass. It is made with the following ingredients:
2 oz Tequila
4 oz Orange juice
3/4 oz Grenadine

Stir or shake tequila and orange juice with ice until chilled. Strain into glass half full of ice cubes. Pour in the grenadine and allow it to settle at the bottom of the glass, creating the ‘sunrise’. Stir before drinking.

For a “Tequila Sunset,” substitute Grenadine with blackberry brandy.
 
(Oxford English Dictionary)
tequila sunrise, a name given to cocktails containing tequila and grenadine.
1965 O. A. MENDELSOHN Dict. Drink & Drinking 336 Tequila Sunrise, mixed drink of tequila, lemon juice, grenadine and cinnamon liqueur.
 
29 September 1940, Los Angeles Times, pg. I10:
He ordered a Tequila Sunrise and she said she’d have the same because she’d never tried one.
   
4 May 1941, Helena (MT) Independent, pg. 2, col. 1 ad:
INDIVIDUAL CHAMPAGNE COCKTAIL…
ZOMBIE…
BOO SNOOKER…
RUM BOOGIE…
CUBAN COOLER…
SEA BREEZE COLLINS…
SCARLETT O’HARA…
TEQUILA SUNRISE:
(Tequila and 4 Other Ingredients)
 
18 May 1956, Los Angeles Times, pg. B6 ad:
It’s delicious with
Jose Cuervo Tequila
TRY A TEQUILA SUNRISE
Fill glass with crushed ice
One jigger Cuervo Tequila
One teaspoonful grenadine
1/3 teaspoonful creme de cassis
Juice 1/2 lime & sparkling water