Slept-like town [topic-は] lively city [to-に] changed.
眠ったような = 'as if it had slept' — used metaphorically for a sleepy, quiet, inactive place. The ように/ようだ family used attributively. 都会 = 'city' (more citified than 町 'town'). にぎやか ('lively, bustling') is a classic な-adjective.