The display windows styled like washing machines at the Lexington Avenue superstore will tip you off to Diesel's industrial edge. They give their mainstay, denim, various finishes, from a dusty-looking indigo to superfaded. Diesel Style Lab carries a secondary line with futuristic leanings in graphic prints and souped-up fabrics. The Diesel Denim Gallery will even launder your purchase for you. Subway: N, R, W, 4, 5, 6 to 59th St./Lexington Ave. Other locations: 1 Union Sq. W, at 14th St., PHONE: 646/336-8552; Subway: L, N, Q, R, W, 4, 5, 6 to 14th St./Union Sq. Diesel Style Lab, 416 West Broadway, between Prince and Spring Sts., SoHo, PHONE: 212/343-3863; Subway: C, E to Spring St. Diesel Denim Gallery, 68 Greene St., between Spring and Broome Sts., SoHo, PHONE: 212/966-5593; Subway: C, E to Spring St.