Hello,
An Workbook is an Azure Resource, meaning that you can control who have access to that specific resource by configuring the Access Control (IAM) settings on it.
You should be able to find the Workbook Resource (usually in the same Resource Group where you have the Sentinel Workspace) and then from the Access Control pane of that Workbook resource, you can specify what users have permissions.
Make sure that the same users with permissions also have access to the Log Analytics Workspace (Sentinel Reader Role) so that the visualization from the workbook will load.
BR,
George