The cartoon shows an Easter Bunny (or Easter Rabbit) delivering Easter eggs in a basket. He tells a little blue bird flying beside him, "It's a sweet job. I work at home in my jammies and I only have to make deliveries once a year."
The cartoon features two examples of American usage.
1. Sweet is used in expressions of assent or approval. • Yeah, I’d like to come to the party. Sweet. • That's a really sweet deal.
2. Jammies are an informal word for pajamas (spelt 'pyjamas' in British English).