In my research on the Paloma I have come across many variations on the drink, so I thought I'd link to them here.
Typically the Paloma is made with tequila (always use 100% agave!), grapefruit soda such as Squirt or Jarritos, a squeeze of a lime wedge and a pinch of salt. Esquire's standard recipe is here. A version using fresh grapefruit and soda water is here.
Here are some Paloma variations from around the internet.
Blood Orange and Thyme Paloma by Airda Molenkamp [recipe]
Nuestra Paloma by Thad Vogler of Beretta, SF. It contains St. Germain, bitters, Cointreau, and grapefruit juice. [recipe]
The Charred Grapefruit Paloma by Warren Bobrow [recipe]
Paloma, Mi Amante by Paul Clarke - A Paloma using strawberry-infused tequila. [recipe]
Paloma Variation - A Paloma using IPA beer, plus tequila, grapefruit cordial, and lime. [mentioned here; no recipe]
Palomita - A Paloma without tequila; just using Coinreau, lime, and grapefruit. [recipe]
Green Palomarita - Mezcal, lime, grapefruit, Chartreuse [recipe]
Dove & Daisy - Tequila, lime, Aperol, orange liqueur, salt, soda water. [recipe]
La Paloma - Grapefruit liqueur, tequila, grapefruit juice, lime, soda. [recipe]
Cantarito - A Paloma variation using lemon, lime, and orange juices in place of the lime squeeze. [recipe]
Paloma Brava by Dushan Zaric - Contains tequila, lime, orange, grapefruit, grapefruit soda, agave nectar, and salt. [recipe]
La Canterita by Ashley Miller - Tequila, triple sec, agave nectar, grapefruit, lemon, lime, orange. [recipe]
Strawberry Paloma with strawberry-infused tequila, honey, lime, and grapefruit. [recipe]
Reunion Cooler by Jennifer Colliau- Tequila, peppercorns, pineapple, grapefruit peel, lime. [recipe]
The 212 by Aisha Sharpe and Willy Shine - Tequila, Aperol, grapefruit [recipe]
Siesta by Katie Stipe - Tequila, Campari, lime, grapefruit, simple syrup [recipe]
Acapulco by Salvatore Calabrese - Tequila, rum, grapefruit, pineapple. [recipe]
Cardarita by Ago Perrone - Tequila, almond-cardamom sugar, grapefruit, Galliano, ginger ale [recipe]
Salty Chihuahua - Tequila, grapefruit juice, salt [recipe]
Ginger Paloma - Ginger-grapefruit syrup, tequila, lime, club soda [recipe]
Tequila Fresa Punch - Starwberry-infused tequila, triple sec, orange, lime, grapefruit soda, orange bitters [recipe]