THE Hongkong Academy for Performing Arts is presenting Looking for Rainbow in Cantonese from May 19 to 22 at 7.30 pm, with a Saturday matinee at the Academy Drama Theatre. With music and song, Looking for Rainbow is an adaptation, by Colin George, of four medieval plays performed in the northern English town of Wakefield in the 15th century. This is an opportunity to see a Western classic performed by Chinese actors, in a production that captures the contemporary flavour of the original. Looking for Rainbow , is translated into Cantonese by Jane Lai with music specially composed for the production by Hugh Trethowan. The design is by School of Technical Arts (Theatre) students Andy Tam (set), Karin Chiu (costume), Tiffany Yiu (lighting) and Bonnie Chung (sound). It is performed by final year students of the School of Drama. Stage movement is by the Head of Modern Dance, Tom Brown. Tickets at $70 and $50 (adults); $55 and $45 (Society of APA members); $28 (full-time students and senior citizens) are available at URBTIX outlets. For reservations call 734-9009. The School of Drama will perform ''Looking for Rainbow'' in two cities in the United States - San Francisco and Los Angeles - next month.