CUSAT is one of the most renowned Institutes of Cochin that offers a variety of professional degree courses.
The entrance exam has around 125 objective type questions. The questions are from physics, chemistry and mathematics subjects.
As you have asked about the CUSAT exam preparation textbooks, check below for the information

CUSAT Preparation: BEST BOOKS For Mathematics

1. NCERT Mathematics for Class 11th and 12th Very good for theory and expect direct questions from the book.
2. Mathematics by R.S.Agrawal Basic book of class 11th and 12th will help you develop sound base for preparation.
3. Objective Mathematics by R.D.Sharma Very good for developing concepts involve in mathematics you will find variety of question in the book.
4. Previous years papers of CUSAT Great for practice in time limit

CUSAT Preparation: BEST BOOKS For Physics

1. NCERT Physics for Class 11th and 12th Very good for theory and small direct questions asked in CUSAT
2. Concepts of Physics by H.C.Verma Very good developing basics of physics and understanding of the subject.
3. Understanding Physics by D.C.Pandey Good for Practice particularly questions of different variety are available
4. Previous years papers of CUSAT Great for practice in time limit

CUSAT Preparation: BEST BOOKS For Chemistry

1. NCERT Chemistry for Class 11th and 12th Very good for theory and Expect Direct Questions from the book
2. Physical Chemistry by P.Bahadur Very good developing basics of chemistry and good for numerical. you can skip difficult questions for CUSAT
3. Inorganic Chemistry by O.P.Tondon Good for Practice particularly questions of different variety are available
4. Organic Chemistry by Arihant Publication Lot of Questions of Different type, must to develop concept and application skill of organic chemistry
5. Previous years papers of CUSAT Great for practice in time limit