Forty inch IDE cables exist by the way. Not real common, few places still have them.

One of the classic ways to hook up a CDROM on a 486 was through the IDE header on a sound card, you don't actually need a BIOS for a CDROM, well not until later pentium BIOSes and drives had the capability to boot them. So if you haven't got your soundcard sorted yet it's not all that much more trouble to find one with an IDE interface. Be sure it's IDE though there were some early 40 pin non-IDE ones.

I'm not very sure of what you're asking for, but let me try:

That card is made of two functionally independent parts - a proprietary (relatively to estabilished PC standards) 16-bit to 8-bit interface converter, and a memory-mapped option ROM socket (which is typically used for the "XTIDE Universal Bios", an option ROM that in this case provides a bootable driver for the other part but can have other purposes and be used standalone)

It is intended for older computers (those with an 8-bit bus, which tend to be called "XT"s in the generic meaning 😀 ), you can use it with a 16-bit ISA computer and it will work fine for its intended purpose, but you'll do better with a 16 bit IDE card (which can be rather simple: Re: Best ISA super i/o chipset? )

"Its intended purpose" isn't CDs or other ATAPI things, for neither of the two parts (even though future expansion to those is theoretically possible)

You could buy/make a longer cable (probably off standard, but it's not like you're going to use the top speeds of even 40-pin IDE) or get one of those IDE cards (possibly even as part of a superIO or sound card), as long as it can be configured to be the "secondary channel", and use that for your CD drive (I bet there's enough stupid software that requires an HDD as primary master, and the secondary channel won't be bootable anyway... unless you rewrite the firmware or add an option ROM that provides the functionality, as could be the XTIDE Universal Bios if you wanted to use 2 HDDs 😁 )
The latter is probably the smarter choice - both drives can be accessed "simultaneously" and you skip the fun of master/slave interactions in early 90s stuff!

If you end up with a secondary interface without a bootrom there's a util on old SIMTEL archives called something like 4Drives which is actually crippled until registration to only one drive on the secondary, but that's usually fine if you just want another storage drive with the CDROM on there. But this is an extra info dump thing and something you might not wanna bother with at the moment.