De modo geral:

S/A = Corporation
Presidente do Conselho = Chairman
Vice-Presidente do Conselho = Vice-Chairman
Presidente de SA = Chief Executive Officer
Diretoria = Executive Board

Diretor Presidente / Diretor Geral = Managing Director
Vice-Presidente = Vice Managing Director
Diretoria = Executive Management

A chief executive officer (CEO) or chief executive is the highest-ranking corporate officer, administrator, corporate administrator, executive, or executive officer in charge of total management of a corporation, company, organization, or agency, reporting to the Board of Directors and/or the Organization's Owner(s). In internal communication and press releases, many companies capitalize the term and those of other high positions, even when they are not proper nouns.

Managing director is the term used for the chief executive of many limited companies in the United Kingdom, Commonwealth and some other English speaking countries. The title reflects their role as both a member of the Board of Directors but also as the senior manager.

At investment banks and other financial institutions, "managing director" does not refer to the chief executive but can rather refer to the head of a major business unit.

The term Chief Executive (or its American equivalent "Chief Executive Officer" or just "CEO") is in general usage in the United Kingdom for the senior executive of public limited companies, charities and Executive Agencies.

At subsidiary companies usage is more variable, with managing director often preferred.

Fonte: Wikipedia