Is it possible to use the same sata cable for SSD drive bay?

You do realize you have three SATA ports in your system: HD, Optical drive & Spare

So you don't need to take out your optical drive to add the SSD (it will use the spare port). If you wanted to have three drives (HDD, SSD1 & HDD2 or SSD2 for the optical drive) then I could see that might make sense!

Here's the IFIXIT guide to add in the Spare port SSD: Installazione del Kit Doppio Disco nell'iMac Intel EMC 2429 da 27".

If you want to push your system to the max then you could do this: Installazione dell'SSD Dual Drive nell'iMac Intel EMC 2309 ed EMC 2374 da 27"

The part cost for either is the same ($20 US), yes the first is a bit more work but you don't loose your optical drive and you still need to add in the cost of the case to hold your drive. Lastly, the optical drives SATA port is only SATA II (3.0 Gb/s). So in my option I would do the first way as it will give you the higher speed I/O SATA III (6.0 Gb/s). And I would set it up as the boot drive.