The rising usage of Social Network Sites for interacting with contacts from multiple social spheres poses new privacy challenges and increasingly prompts users to manage their online identities. To convey a consistent image of the self when interacting with a group of contacts, at first awareness of previously used social roles is needed. However, existing tools on Social Network Sites to increase such awareness are often spread over different interfaces and the user is left to figure out which contacts have access to which shared items. To address these problems, we introduce the Access Policy Grid, a new visualization offering a bird's-eye view on defined privacy settings that allows identifying social roles and inconsistencies therein. To evaluate our visualization, we present the results of a laboratory experiment involving 32 participants in which we compare the Access Policy Grid to the native Facebook interface. For five out of six research questions, our results show that the APG outperforms the Facebook interface significantly in terms of at least one of the three investigated aspects (accuracy, confidence, and time-to-task completion).