I have server with CentOS release 5.9 (Final).
I noticed that it does not have file: /etc/udev/rules.d/70-persistent-net.rules
Except that it works OK. Stable and does it work although its old OS.

Is there any way to generate this file?

CentOS is based on RHEL.

I have several RHEL5 servers including RHEL5.9, RHEL5.10 & RHEL5.11. None of them has this file.

I also have multiple RHEL6 servers and most (but not all) have the file. On RHEL6 (and therefore CentOS6) the file is initially created by command /lib/udev/write_net_rules which is supplied by the udev RPM used on RHEL6.

The RHEL5 (and therefore CentOS5) udev RPM does NOT contain that utility.

You can manually generate any udev file with your favorite text editor but the fact this doesn't exist makes me question the need for it on RHEL5/CentOS5.

There is discussion about the file for RHEL6 at:
https://access.redhat.com/discussions/1240213