The ER diagram is constructed from the specific ERD graphic elements. There are used 2 types of ERD notations: Chen and Crow’s Foot.
A complete set of work flow shapes, notation & symbols for ERD, entity relationship stencils, included in Entity-Relationship Diagram (ERD) solution for ConceptDraw DIAGRAM software, makes drawing diagrams based on ERD notation as smooth as possible. Relationship Diagram Interior Design
https://www.conceptdraw.com/examples/relationship-diagram-interior-design