Some ideas from an old CL:
Your company profile and a possible fixed position attracted me. XXX inhabits not only an outstanding reputation among corporate institutions and governments around Europe. As importantly, it is its reputation among its employees. From what I heard, it seems to me that XXX takes tremendous care about the quality of its employees. I not only share but also live the values XXX espouses: taking initiative, being curious, having an entrepreneurial spirit and a global mindset. Your Investment Banking department is the right choice for me, because it gives me the opportunity to contribute with the skills I have gained during my studies and previous internships.
Hope this help a bit.