It's nice to know your organization has a handbook for new employees for good onboarding. Putting the names of managers in different departments in the handbook is a matter to be decided by your management.
In many MNCs where employee handbooks are in place, only the CEO/MD/COO or topmost ranks are allowed to be printed in the handbook along with a detailed profile of the person.
Here, apart from the essential organizational information, you can clearly show the organizational hierarchy with the designations, roles and responsibilities, business functions, regional structures (for MNCs), and so on.
Since lower-level employees tend to leave the job more than top-level executives, it would be a good idea to print your handbook only with top-level people's profiles. Usually, CEOs and MDs serve for a long time in organizations.
At the same time, you can use the same book in a more detailed form as a soft copy in PDF format, which can include all your present managers starting from top to bottom positions with their designations and salutations. It is easy to include their photos and brief profiles and can edit it whenever needed.
On the first day when an employee joins, they are welcomed with this soft copy of the handbook sent from the Corporate HR department to their new Email ID (official) along with other statutory forms to go through and get filled up, and returned to the HR department on the same day itself.
You can add a lot of other information in corporate PowerPoint presentations with commentary and videos to let the new joiner get accustomed to the new environment very soon. These can be uploaded in the common shared drives of your organization or in the local intranet. In organizations I have worked (and currently working), we follow these practices.
Thank you.