In a well voted comment in a question about responsibility to detect plagiarism it notes that it rests with the author. This well voted answer on a now on-hold question about removing plagiarized parts of a thesis states the following which could read to imply some responsibility for the supervisor.
If you think/know that parts of your thesis are plagiates you and/or your supervisors seem to have failed.
Regardless of the above in regard to responsibility of detecting plagiarism if a student does plagiarise, I assume it must have some impact on the supervisor.
Has there been any cases that have shown what is the effect on a supervisor (career wise/reputation etc.) if a graduate student has been found to have plagiarised?