Hmm, you are a bit under level for Master. Do you have any +RCV eggs on that Siren? What is it's skill level? At level 17, you will lose about 250 HP per hit from the Skydragon. I think you can recover that difference using Siren's skill.
Team:
Leader - Siren
Chaos Devil Dragon
Graviton Earth Dragon
Dragon Knight
Firedragon Tyrannos
Friend leader - Lightning Holy Dragon
Should be about 9000 HP, depending on your friend leader.
If your team cost is too high, you can try moving out the Dragon Knight and Firedragon for whatever you can squeeze in that has the highest HP. The CDD and GED are required for their skills and damage output.
Strategy: If you get more than 2 devils on round 1, you probably won't make it. Otherwise, tap on a devil and do as much damage as you can as fast as you can. Once you are down to one or two monsters in that first round, you need to stall. Single matches, heart orb matches, or matches for a color that does no/little damage. You need to get those Dragon skills up and active. After 15 turns, clear out the first round (but don't use the skills yet). Turns 2-4, activate a ripper dragon and blast away. Should wipe each round, or be very close. Turn 5 is midboss. Use this time to charge the dragon skills back up. After 15 turns, you can move on. Turns 6-7, blast with GED and LHD again. On turn 8, if you aren't surrounded by devils, wear everything down normally and try to charge up the dragons again. Turn 9 will be really tough. 2 Angels will hit for more than you can heal, especially if they are on the same timer. Focus on one and unload as much as possible, including the Chaos Devil Dragon skill you should have saved. Hope you make it. Once you get to the Skydragon, it shouldn't be too much issue. It will take a while, since his HP is pretty massive compared to your damage output. Match as quick as you can, and unleash CDD every time he is available. Every so often you will need to pop that Siren active skill, so keep red orbs around. You will need them to make up the difference in RCV vs resisted damage.
Skydragon is not a 100% drop on Master, so you may need to do this more than once. If you are having trouble healing or getting past the Angels, you might consider putting the Keeper of Flame into your team and using his damage reducing skill when necessary.