You are able to visually see all the resources in an AWS VPC by hovering your cursor over the security groups in the attribute pane.
The connected resources belonging to the security group you are hovering over will be highlighted with a green border. In the below interactive diagram, five Elastic Load Balancers and seven EC2 Instances are highlighted when hovering over the 'demo-internal-servers' security group.
Further details can be viewed by selecting the security group from the list in the attribute pane.
This will display all the resources both visualised and not. For instance EC2 instances contained in autoscaling groups and network interfaces connected to this security group, that are not visualised on the diagram can be viewed in this list.
You are able to continue drilling down through the resource attribute data by clicking on the resource you are interested in.