Recommended and mentioned products
Online diagramming application
Upvote for draw.io. We have a way larger network here and the offline Windows application version works well for me.
LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
You could try lucidchart.com or draw.io. I have used both.
Netdisco is an Open Source web-based network management tool first released publically in 2003.
We have started to use netdisco - http://netdisco.org. Might be overkill for your network, but it will let you monitor, manage, and map out your network from one place, using snmp. We are using it for HP/Aruba and Cisco.